The present invention relates to tape loading systems for tape transports and more particularly to semiautomatic tape loading systems for transports of the type wherein tape traveling between a pair of reels is moved past a recording/readout station by capstan means.
Capstan driven tape transports, particularly those used for magnetic recording and readout in incremental steps, are well-known in the art. In transports of this type, the capstan means may, for example, consist of a single capstan positioned in the vicinity of the magnetic recording/readout head. The tape characteristically travels between a pair of reels, one of which may be permanently mounted on the machine and the other removable therefrom to store the tape. The reels are selectively adapted to dispense or receive the tape, with loop chambers frequently straddling the capstan means along the tape path and serving a buffering function between the rapid tape motion imparted by the capstan means and the slower-moving, relatively high-inertia tape reels and associated reel motors. While the capstan means characteristically operate under control of an externally derived signal, e.g. one derived from an associated computer, the reels are independently rotated, usually under control of signals derived from a device which monitors the length of the tape loop in each loop chamber. In order to retain tension in the tape, each loop chambers conventionally has vacuum pressure applied thereto.
In prior art tape transports of the type described, the tape is characteristically loaded either entirely by the manual intervention of the operation, or in a fully automatic manner. Manual loading requires extensive assistance from the operator over and beyond the act of placing and locking the tape reel on the appropriate spindle of the transport. The operator is required to thread the leading end of the tape carried by the removable tape reel, through the entire operating tape path, including the various tape guides, the vacuum chambers and the intermediately positioned capstan means, all the way to the permanent tape reel to which the tape end must then be secured. The time involved in this operation, which may be required many times a day in the average computer installation, is normally greater than what is considered tolerable, particularly so where the same operator is further required to attend to a number of other machines of a computer system carrying out various and diverse functions. Further, the chance of error for all but the most experienced operators is high. Improper tape loading risks the destruction of at least a portion of the tape, in addition to the accompanying time delays. Further, full manual tape loading further requires that the vacuum chambers be opened, which gives rise to the possibility of introducing dirt and causing a malfunction of the transport.
The above-described disadvantages of manual loading are largely avoided where apparatus is provided to carry out fully automatic tape loading. Here, operator intervention is not required except to place the tape reel onto the spindle of the transport. However, the cost of a fully automated tape loading system is relatively high. Further, while operator error is avoided, equipment malfunction may still occur and such equipment has been known to operate at relatively low reliability. Problems have occurred in conjunction with the locking of the removable reel in tape transports having fully automatic tape loading system, as well as with the locking of the leading end of the tape to the permanent reel of the transport. In addition, the complexity required of fully automatic tape loading systems, usually means that they are expensive, as well as difficult to maintain in proper operating condition. Thus, neither fully manual nor fully automatic prior art tape loading apparatus has heretofore been able to reconcile the requirements of low cost and high reliability with the delicate handling required by the tape medium.